\begin{table}[htbp]
\centering
\begin{tabular}{P{2.5}P{-2.5}}
  \toprule
  \multicolumn{1}{c}{`数学常数`} & 
  \multicolumn{1}{c}{`物理常数`} \\
  \midrule
  3.14159  & 2.99792 \\
  27.18281 & -17.58819 \\
  \bottomrule
\end{tabular}
\end{table}
